Re: V-27 tube coil: latest results

Hi David, all,
                   My response:

> Original Poster: David Trimmell <davidt-at-pond-dot-net> 
> Hello,
> This is a interesting thing about CW (at least tube based, in my
> experience), to get really high voltage (long sparks!) you must have a
> sharp breakout point extending several inches from the coil, or coil and
> top C. Now, I have obtained spark breakout from a "relatively" smooth
> toroid, but only with extremely nasty kickbacks to the tubes (some sparking
> between plates and filament/grid) or back to the transformer. I cannot see
> any reason to use a toroid in a CW (tube) coil except for a corona shield
> and/or to assist with tuning (I use it for both), only use a protruding
> breakout point.
> Question: So, why do we have such a different response with CW -vs-
> Disruptive coils (spark gap...)? Any body ever try to determine the voltage
> of CW coils? I doubt a spark length comparison with disruptive coils would
> be very close...

In the disruptive coil, you are hitting the secondary with a lump of 
energy (which might or might not be sufficient to generate a voltage 
that will cause sparks to fly. In a CW coil, you are ringing the coil up 
to a level governed by its losses (1/Q in other words) and the ability 
of the oscillator to supply those losses. Until such time as breakout 
voltage is reached, the oscillator sees a well behaved load. On 
breaking out, the oscillator suddenly sees a load change. I would 
expect output length would be dependent on the ability of the 
oscillator to supply energy on a continuous basis with an initial 
breakout length governed by the voltage ther terminal reaches.